Alex Pankratov :
Oct 09, 2019
Archiving doesn't depend on the exclude/include setup in the slightest. All it does is it substitutes all "delete" steps with "move to $archive".
Meaning that the discrepancy in behavior you saw was due to what the program perceived in a need of deletion. That in turn depends strictly on the differences between source and destination trees as seen by the program (which _is_ a subject to exclusion/inclusion rules).
When your backup gets out of sync with the source, it's invariably due to using destination snapshot option and making manual changes to the backup tree. (Using a snapshot forces the program to cache destination file index between the runs and to *not* scan destination on all runs except for the very first one).
Then, when you changed the excl/incl rules, it forced the re-scan, so the destination tree was rebuild afresh and picked up whatever discrepancies.